1. Field of the Invention
The present invention relates to a grinding machine and a grinding method for grinding an outer or internal surface of a cylindrical workpiece.
2. Discussion of the Related Art
Heretofore, as grinding machines for grinding an outer or internal surface of a cylindrical workpiece, there have been known those which are described in JP7-214466 A (hereafter referred to as Patent Document 1) and JP8-168957 A (hereafter referred to as Patent Document 2). Each of the Patent Documents 1 and 2 describes performing a retraction grinding. The retraction grinding referred to herein means a grinding which is carried out as a grinding wheel is moved in a direction to go away from a cylindrical workpiece, after an advance grinding which is carried out by moving the grinding wheel in a direction to be pressed against the cylindrical workpiece. In the advance grinding, a bending or deformation occurs on the cylindrical workpiece because the grinding wheel is pressed against the cylindrical workpiece. Further, in the advance grinding, a residual grinding amount E(θ) differs in dependence upon the rotational phase θ of the cylindrical workpiece. Then, in the retraction grinding, a residual grinding portion which was left without being ground in the advance grinding is ground as the amount of the bending which occurred on the cylindrical workpiece in the advance grinding is decreased. By performing the retraction grinding in this way, it becomes possible to remarkably shorten the grinding period of time in comparison with that taken where the whole of the grinding is performed by the advance grinding.